WE will need fossil fuels like oil and gas for the foreseeable future. So there’s really little choice (sigh). We have to press ahead with fracking for natural gas. We must approve the Keystone XL pipeline to get Canadian oil.

This mantra, repeated on TV ads and in political debates, is punctuated with a tinge of inevitability and regret. But, increasingly, scientific research and the experience of other countries should prompt us to ask: To what extent will we really “need” fossil fuel in the years to come? To what extent is it a choice?

As renewable energy gets cheaper and machines and buildings become more energy efficient, a number of countries that two decades ago ran on a fuel mix much like America’s are successfully dialing down their fossil fuel habits. Thirteen countries got more than 30 percent of their electricity from renewable energy in 2011, according to the Paris-based International Energy Agency, and many are aiming still higher.

Could we? Should we?

A National Research Council report released last week concluded that the United States could halve by 2030 the oil used in cars and trucks compared with 2005 levels by improving the efficiency of gasoline-powered vehicles and by relying more on cars that use alternative power sources, like electric batteries andbiofuels.

Just days earlier a team of Stanford engineers published a proposal showing how New York State — not windy like the Great Plains, nor sunny like Arizona — could easily produce the power it needs from wind, solar and water power by 2030. In fact there was so much potential power, the researchers found, that renewable power could also fuel our cars.

“It’s absolutely not true that we need natural gas, coal or oil — we think it’s a myth,” said Mark Z. Jacobson, a professor of civil and environmental engineering and the main author of the study, published in the journal Energy Policy. “You could power America with renewables from a technical and economic standpoint. The biggest obstacles are social and political — what you need is the will to do it.”